Generally speaking and with reference to FIGS. 1 and 2, a photovoltaic module 1 is formed by a plurality of bifacial solar cells 2, each having an active front face 20 and an active rear face 21, that can capture and convert to electrical energy photons from an incident light radiation falling on said front and rear faces. These cells are spaced apart from one another within a structure 3 formed by a front plate 30 transparent to incident radiation and placed opposite the front faces 20, a rear plate 31, transparent to said radiation, and placed opposite the rear faces 21, and a frame 32 for sealing the assembly in order to improve resistance and seal the structure.
Since the electrical power generated by the photovoltaic module depends in particular on the incident light flux, these photovoltaic modules are generally placed on roofs or as a replacement for the roof, to benefit from maximum brightness. The front plate of the structure is thus preferably made from a transparent material that has a high light transmission coefficient and is impact and weather resistant.
Furthermore, since the cells are arranged to be spaced apart from one another, photons may pass through the structure via the gaps separating adjacent cells, without interacting with the cells. Capturing these lost photons to send them back towards the active rear faces of the cells constitutes a solution for improving capture, and hence photovoltaic module efficiency. To do so, a reflecting plate may be placed opposite the rear faces of the cells. The surface of this reflecting plate is in particular provided with reflective means such as mirrors, or refractive means such as prisms or lenses.
For example, document U.S. Pat. No. 6,410,843 proposes the use of a continuous reflecting plate, i.e. with dimensions equal to those of the rear plate of the structure, the surface of which has rough patches in the form of continuously alternating bumps and hollows, in order to capture the lost photons and send them back towards the rear faces of the cells.
Likewise, document U.S. Pat. No. 5,994,641 proposes covering the surface of the reflecting plate with a textured film having raised parts arranged opposite the gaps separating adjacent cells, each raised part having a different orientation depending on its position relative to the cells.
Although these solutions do allow the lost photons to be sent back towards the rear face of the cells, the assembly formed by the photovoltaic module and the reflecting plate is bulky, cumbersome, fragile, expensive and not optimised.
In this context, the purpose of this invention is to propose another reflective device that is free from at least one of the previously mentioned limitations. The particular purpose of the invention is to improve the efficiency of a photovoltaic module, by proposing a solution that can optimise the capture of the lost photons and the return thereof towards the active rear face of the cells. A further purpose of the invention is to propose a less expensive and less cumbersome solution.